MapStruct 和不可变对象

Question

我在使用 mapstruct 和不可变对象时遇到问题。

@Value.Immutable
public abstract class FoobarValue {
    public abstract Integer foo();
}

@Value.Immutable
public abstract class TargetFoo {
    public abstract Integer foo();
}

@Mapper
public interface ImmutableMapper {

    ImmutableMapper INSTANCE = Mappers.getMapper(ImmutableMapper.class);

    public TargetFoo toTarget(FoobarValue foobarValue);
}

主要class测试

public class FoobarValueMain {
    public static void main(String... args) {
        FoobarValue value = ImmutableFoobarValue.builder()
                .foo(2)
                .build();
        ImmutableMapper mapper = ImmutableMapper.INSTANCE;
        System.out.println(mapper.toTarget(value).foo());
    }
}

我得到的错误是

Exception in thread "main" java.lang.IllegalStateException: Cannot build TargetFoo, some of required attributes are not set [foo]
    at org.play.ImmutableTargetFoo$Builder.build(ImmutableTargetFoo.java:158)
    at org.play.ImmutableMapperImpl.toTarget(ImmutableMapperImpl.java:21)
    at org.play.FoobarValueMain.main(FoobarValueMain.java:12)

我的build.gradle如下

ext {
    mapstructVersion = "1.4.0.Beta2"
    immutablesVersion = "2.8.2"
}

dependencies {
    annotationProcessor "org.immutables:value:$immutablesVersion" // <--- this is important
    annotationProcessor "org.mapstruct:mapstruct-processor:1.4.0.Beta2"

    compileOnly "org.immutables:value:$immutablesVersion"
    implementation "org.mapstruct:mapstruct:${mapstructVersion}"

    testCompile group: 'junit', name: 'junit', version: '4.12'
}

根据 reference 这一切都应该开箱即用。我在这里错过了什么？

Answer 1

之所以不起作用，是因为您没有使用 JavaBean 约定。

您需要在方法前加上 get

前缀

例如

@Value.Immutable
public abstract class TargetFoo {
    public abstract Integer getFoo();
}

MapStruct 和不可变对象

MapStruct and Immutables

gradle

mapstruct

immutables-library